Over the last few weeks, we have received increased calls about lawns browning, presumably from lack of irrigation from several of our accounts throughout the Twin Cities, from Blaine to Savage, Plymouth to Woodbury. We’ve dispatched techs who confirmed the function of the irrigation, we’ve increased irrigation, we’ve increased the height of our mowing decks, we’ve skipped mowing in the heat; all things a responsible vendor would do. Yet this continues.
We reached out to our peer circles, and former golf course superintendent colleagues and collectively we believe we have a fungus among us (I’ve always wanted a reason to say that). This fungus is Ascochyta leaf blight. According to an article published by Colorado State University, it is most common when the weather changes from cool and wet to hot and dry… sound familiar?
Fun guys… I mean Fungi can remain dormant in the soil for years until the conditions exist that trigger an outbreak (a party for the fun guys). It becomes visible quickly, sometime over a night, and similar to a cold, it will affect the weakest areas of the lawn first, typically areas with the shortest root system. It spreads extremely easy by foot traffic, rain and lawn mowing. From a distance the straw-colored areas resemble drought stress, hence the call to the irrigation company. Mowing equipment will also pick up the fungus and spread the disease throughout the lawn, creating a stripe like pattern of the disease that resembles fertilizer burn or heat damage, hence the call to the landscaper.
While this disease seems cause for alarm, it will not cause any permanent injury to the lawn because it doesn’t damage the crown or roots of the grass, and due to its sporadic and rapid spreading, a fungicide spray is not recommended. Cultural practices are the best way to help get rid of the disease. Here are some options presented by Fairway Green Inc.:
- Deep infrequent watering to help the roots grow (sound familiar?)
- Keep the lawn height at 3 – 3 ½” in length (should also sound familiar)
- Mow off no more than 1/3rd of the grass plant at a time
- Aerate the lawn regularly in the early fall to help reduce thatch (where disease harbors) soil compaction. This will also help to create a stronger root system and grass plants.
Ascochyta blight will not kill your lawn, it is just ugly. It simply needs to grow out on its own with a little help from you and/or your outdoor stewards. If the conditions remain favorable this type of disease can persist for weeks. After all cultural practices have been done, the only other thing you can do is be patient. Give it time, your lawn will be okay.
None of this is to say you can’t or don’t have malfunctioning irrigation, fertilizer burn or heat damage; this is however something to keep in mind when it seems like everyone has done everything right and there is still an issue.